Mannoroth Mythic Difficulty

On Mythic difficulty, players essentially skip Phase 1. When they first arrive at Destructor's Rise, the Fel Iron Summoners adds are there and can be engaged in combat. However, approximately 7 seconds later - before the Fel Iron Summoners can summon a single demonic minion - Gul'dan slays them, and harvests their power to reanimate Mannoroth. He chooses to do this instead of destroying the first, Doom Lord-summoning Fel Spire.

As a result, players nearly immediately enter Phase 2, but with a twist - since all three Fel Spires are active at this time, players must contend with Fel Imp-losion, Inferno, and Curse of the Legion. This means that Fel Imps, Dread Infernals, and Doom Lords will spawn while players are engaged in combat with Mannoroth.

Doom Lords must be tanked, but even in Mythic mode one tank should hold the Doom Lord until it dies

The player targeted by Curse of the Legion should run close to tanks, use a survivability cooldown, and call for a dispel to spawn the Doom Lord

Doom Spike will deal heavier damage on Mythic mode, so tanks may wish to use a strong survivability CD when the debuff wears off

The tank affected by Doom Spike must run away from the raid before the debuff expires, to avoid splashing Explosive Doom Spike damage onto the raid

Doom Lords will cast Mark of Doom on three random players approximately 12 seconds after spawning, and again every 30 seconds thereafter.

Players affected by Mark of Doom must run out of the raid to avoid splashing Mark Eruption on to other players

These players must intentionally take damage from a mechanic in order to remove the Mark of Doom

Players can ensure this happens by allowing the Doom Lord to cast Shadow Bolt Volley after the Mark of Doom players have spread out appropriately

Players affected by Mark of Doom should use personal damage-reduction cooldowns where possible to mitigate the Mark of Doom and the damage that triggered it.

Fel Imps are also more powerful on Mythic difficulty. When they use their Phase Blink ability to teleport, they will deal Phase Explosion damage when they arrive at their new location. Players should move away from the Fel Imp's Phase Blink indicator to avoid taking this damage.

When Mannoroth reaches 65% health and enters Phase 3, Gul'dan will destroy the Infernal-summoning Fel Spire, but Doom Lords and Fel Imps will continue to spawn. Mannoroth gains the Wrath of Gul'dan ability in this phase.

Mannoroth will choose five random targets and debuff them with Wrath of Gul'dan

This debuff has 40 stacks, and every second it will attempt to apply Gripping Shadows to nearby targets

Each stack of Gripping Shadows that is applied will reduce the player's Wrath of Gul'dan stacks by 1

A maximum of 3 stacks can be leeched off each second in this way

There does appear to be a maximum range, beyond which Gripping Shadows will not pass to another player - players soaking Gripping Shadows must move close to the Wrath of Gul'dan target

Gripping Shadows deals a single pulse of Shadow damage and places a stacking Gripping Shadows debuff on the players it damages

Wrath of Gul'dan lasts 10 minutes, so players must take turns leeching stacks off the Wrath of Gul'dan targets in order to remove the mechanic. It is unclear whether a player with Wrath of Gul'dan can gain stacks of Gripping Shadows from their own Wrath of Gul'dan debuff.

When Mannoroth reaches 30% health and enters Phase 4, Gul'dan will destroy the Doom Lord-summoning Fel Spire, but Fel Imps will continue to spawn. During this time, Mannoroth's Empowered Massive Blast will stun the targeted tank.

It is unclear whether this means that players can continue to tank Mannoroth with their back against the Fel Imp pillar during the final phase of the fight, effectively removing some of the danger of Empowered Massive Blast.

Throughout Phases 2 and 3, the kill priority should be:

Doom Lords

Dread Infernals

Fel Imps

Mannoroth

Mythic Mannoroth was not thoroughly tested on the PTR, so some mechanics may have changed by the time the encounter goes live. This section will be updated with more details as information becomes available.